Apparatus for controlling electrically transmitted musical programs



J. L. ADAMS, JR

Dec. 22, 1936.

APPARATUS FOR CONTROLLING ELEOTRICALLTTRANSMITTED MUSICAL PROGRAMS Filed May 12, 1933 INVENTOR.

Patented Dec. 22, 1936 UNITED STATES PATENT OFFICE APPARATUS FOR CONTROLLING ELECTRI- CALLY TRANSMITTED MUSICAL PRO- GRAMS James L. Adams, Jr., Youngstown, Ohio Application May 12, 1933, Serial No. 670,866

Claims.

tially all broadcast programs, and known as the background-noise or the "noise-level experienced by the mode of transmission involved.

One of the most important objects of my present invention is this material clarification of the incoming signal train of a vast majority of the commonly present man-made static noises now so common to radio-broadcast reception.

Another object of prime importance is to provide means for very effectively shielding the incoming signal train from lightning inductive effects, and similar atmospheric disturbances of the type so highly annoying to the listener.

A further valued object is to provide simple means for efiectively putting the broadcast and/or wire transmitted programs on a pay basis, so that the customary sponsoring of such programs, with its attendant advertising nuisance elements, can eventually be eliminated, and thoroughly good programs substituted for the often mediocre and offensive variety now so predominant in the field, at least in so far as this country is concerned. I

An additional object is to provide a switchstation, or control box, the interior of which can not be tampered with by the customer, access thereto being only available to the programtransmitting company, or the telephone company operating as its agent, as the case may be, by appropriate key.

An added object is to provide convenient means for bringing not only the transmission wires for the program service, but also the customary telephone twisted pairs, into the receiving customers premises through a metal covered cable common to both, thereby consolidating the services, and aiding in elimination of extraneous noises.v

An essential object is to provide convenient means whereby a customer can readily select from a diversity of excellent programs of the nonsponsored type, or if he so prefers at any time, 55' he can th ow-ov o his Own cu omary outside aerial and receive the regular broadcast programs.

An incidental, but yet important object, is to obviate substantially all of the usual spilling over of the more powerful incoming programs 5 into the programs being received on neighboring channels, as now commonly attendant to normal wireless reception. That is, my invention provides high selectivity on the non-sponsored type of audio-frequency programs transmitted. Yet 10 another object is to provide programs free from the usual fading" and the mushiness, that is, the distorted and garbled speech and music incident to the periods of minimum received signal strength. 15

Other objects of importance will be obvious to anyone skilled in the art to which my invention appertains.

With all the above and other objects in mind,

I have provided a simple type of apparatus for go attaining concomitantly substantially all the objects enumerated, in a convenient and practical way.

In the drawing, Figure 1 shows a typical wiring diagram of my proposed invention; 25

Figure 2 is a similar wiring diagram showing the customer's station equipment more in detail;

Figure 3 shows a developed cross section of my adapter-plug, devised so as to show all the plugs and connections in one plane, for simplicity of exposition.

In all the figures, identical parts are designated by the same part numbers and letters. primes and sub-numbers being aiiixed in some cases, so as to distinguish between the two wires 35 leading to the same tube filament, or the two wires which connect to opposite sides of a break made in a given line, as F1 and F2 of Figure 3.

The drawing is shown for purposes of illustration only, and not as determining the limits 4 of my invention, or of its possible applications, and show a type of apparatus which may be readily applied to, or if desired even built in with, any customary type of standard radiobroadcast receiver, without great alteration 45 thereto.

In accordance with the present invention, and referring now more particularly to Figure 1, there may be provided an apparatus including the control-box ll, metal, wall-mounting typ closed by the cover I2, substantially all the major portion of which has been broken away in order to show the interior construction of the box, but leaving enough to indicate the position of the riveted-on preferably of fully-enclosed,

hinges l3, and of the multi-tumbler Yale or equivalent lock I4, it being noted that the hinges will be of such type that the pins can not be withdrawn, (as by welding or brazing them into position,) and that the mounting screws |5 will be non-accessible except after opening the control-box by its proper key.

Furthermore, that even if the box were yanked oif the mounting wall, then no assembling screws of any sort will be found present upon the back face of said box, accessible for any tamperin operations thereon, from the rear.

Entering the control-box at the top, via the grip-collar or split-bushing H5, is the lead-covered or equivalent metallic sheathed cable I1, indicated in dotted outline, and which is clamped solidly into place within the box, by the clamping-screw l8, also accessible only from the box interior.

Entering the control box H through this cable H are the plurality of audio-frequency transmission line taps to 8 respectively, but which may include a greater or less number than here indicated, all shown single-wire for the sake of clarity, and appropriately connected in sequence to the similarly numbered points on the program-selector switch I3, here shown single-pole, for simplicity of illustration, but in reality usually of double-pole type, as indicated in the succeeding figure. The handle 20 of this switch is insulated from the latter, and made removable, so as to permit ready closure of the control-box lid, or such handle will be mounted directly in such lid, with a slip-key to ensure proper positioning whenever the lid is closed. The line numberings shown will be repeated upon the cover of box, and a pointer provided to take the switch-arm l9 position there, so that the position of the latter will be indicated upon the box exterior.

Also entering the control-box N, there will usually be provided the radio-antenna down-lead 9, and if the customer is provided with a phone, there will be its incoming line ID, the former entering the box via the highly insulating bushing 2|, and the latter via branch cable H, in turn leaving the box via insulating bushing 22 and proceeding either under metallic cover or in the open, to the customer's telephone ringer and connection-box 23, and on to the phone proper 24, with a line to ground at 25. As the lines entering top of control box H, are shown single-wire, for simplicity, change-over to twowire showing has been indicated by brackets, as at 25. Box II, and cover I2, may, if desired, each be provided with a drilled, projecting ear 21, through which cusomary twisted wire hairpin loop 28, and soft metal seal 29 may be attached, to further ensure against tampering.

Also emergent from the control-box via another metal sheathed cable 30, with the splitbushing 3| clamped solidly thereon by the clamping-screw 32, likewise made accessible from the interior of control-box only, are certain wires F1, F2, A, and P1, leading to the standard radio receiver set 33, shown at the left of this figure, and of which wires A goes to the customary antenna binding-post on the radio-sets terminal board, while the other three go to the special adapter 84 shown in Figure 3, and positioned between the detector tube base 86 and its customary receptacle, by inserting the adapter 34 in place first in the receptacle, and then placing the tube base 86 in it. In this radio receiver set 33, I have indicated the ground Connection at Gd, with a tap attached directly to the metal sheath of cable 30 by the clamp at 34.

In this elevation of the set, Sw. indicates the on-and-ofi switch; Vol. the volume control; Dial, the tuning dial; and L. S. the loud-speaker position, as usual.

Reverting now to the control-box again, I preferably place therein a double-pole, doublethrow change-over switch 35, the two poles of which are insulated from each other by the crossbar 35, but operated together by the insulated handle 31, which projects from the lower side of box H, and may be thrown to the left to receive radio-frequency broadcast programs through space or to the right to receive voice or music bearing audio-frequency programs brought in from distant points through the transposed open wire lines, or preferably twisted-pair lead-cable transmission lines 38 to 43, inclusive, or the twisted-wire lines from local broadcast stations 44, 45, into the telephone exchange or equivalently functioning structure 46, and out through the lead covered multi-pair cable 41, from the entertainment or E section of which taps are taken from the wires 48, 43, 50, etc., at points of entrance to customers premises, as at 5|, 52, 53, etc., 5|, 52, 53 etc., 5|", 52", 53", etc., where the cable |1 previously mentioned, or the similar cables l1, and I1" lead to the respective control-boxes and the contained wires emerge at the proper points on selector switch i9.

Customary telephone twisted pairs for regular telephone service enter the exchange 46 via lead covered cable 54 as lines 55, 55, 51, etc., and after passing through the usual selector switches (not shown), emerge in the T section of cable 41, and are taken off in sequence to the successive telephone customers premises via the taps 53, 59, 60, etc., and appropriate lines, one of which I has been described as going through the lead cable l1, into and through the box H to the parts 23 and 24, of the usual customers telephone equipment.

It has not been deemed necessary to designate all the tapped points shown in the T and E sections of cable 41, as the further connections are self-evident.

One pole of selector-switch I3 connects at centre with the wire leading to the single-pole, single-throw disconnect switch used by the program distributing company to disconnect customer in case he is careless about paying for programs rendered. This switch is entirely nonaccessible to customer. All wires are shown from here on.

The remaining terminal of this switch 6| may connect to and through the few-turn primary 62 of an audio-transformer 63, to point 54 on the upper side of right-hand throw of switch 35, then through point 65, and wire 66 to the remaining pole of selector l9, but which can not be shown here because of the one-wire diagram used on the latter. This will be shown in full, however, in connection with Figure 2.

The many-turn secondary 61, of transformer 63, may connect at its upper end to the positive side of a C-battery, the negative of which goes to grid 68, of an audio amplifier tube 69, whose plate 10 connects directly to the P1 line through cable 30, at left side of control-box ll, while lower end of secondary 81 proceeds to one end of filament 1|, and also to the frame of box at 12. Opposite end of filament goes to point 13 on lower right side of switch 35, whose points 14 and 15 are connected together and also to F1 lead going to radio receiver set 33, and adapter 84. Point 16 connects to F2 line in same cable. Antenna 3 connects to point .11, on upper left side of switch 35, and point 18 goes to antenna binding-post A on the radio receiver.

On account of the impeding factor introduced by the passage of radio-frequency waves through the interior of a metal-sheathed cable, it may be better to shorten this length of cable 30 as much as possible, as by mounting the control-box ll directly on the side of, or underneath the radio receiver set 33, or if this is impossible, then to carry antenna 9 into, and lead A from point 18 out of, the control-box via the same insulating bushing 2|, and across the air to point A on radio connecting panel.

I believe that the signals through leads F1, F1, and P1 will be not materially affected, provided cable 30 can be made very short, since here the current flow proceeds both ways through the same opening in the metal sheath, and the impulses are not so .muchmodified thereby, in eonsequence. 19 indicates an insulating coupling in shaft of handle 31.

An amplifying tube has been included in my control-box H, as the preferred construction, but this inclusion may not always be necessary, if the delivered signals through lines 48, 49, 50, etc., of the E section of cable 41, are sent out from exchange 46 after passing through adequate amplifying means there, (not shown).

In such case the transformer 53 will probably be retained, however, so as to isolate the incoming lines from the 'customers radio receiver equipment, the small C-battery shown connected with upper end of secondary 61 will be omitted and replaced by proper isolating condenser, and point 68 directly connected to the lead shown at 10, while the lower end of 61 will go directly to point 12, grounded on frame of box, and to nothing else, there being no filament present in this case within the box, but the F1 and F; leads to switch will remain as before, so as to cut out the lighting of detector tube on radio receiver set, whenever signals are being brought in from the audio-frequency lines Si, 52, 53, et seq. to detector plate.

Referring now to Figure ;2 I have again shown the wiring diagram of the control-box ll of my invention, but with the connections to selectorswitch I! shown in full, instead of one-wire, as before, and with a typical set of connections for the radio receiver set 33 added at the left.

- The radio receiver wiring-diagram Figure 2 covers simple, battery-operated, non-screen-grid tubes, but necessary changes to bring more nearly up to date and accommodate new screen-grid tubes, or those ofthe alternating-current heated filament type, will be self-evident to anyone skilled in the art.

I have shown two stages of tuned-radio-frequency (T. R. F.), a detector, and two iron-core audio-frequency transformer stages, with output leads to loud-speaker (L. S.), A, 13, and C batteries so labelled, a filament lighting switch (Sw.) filament rheostat (R), antenna (A') and ground (Gd) binding-posts'on terminal panel, and the points of contact P1, F1, and F2, as made by the adapter 84 covered by Figure 3.

As the exact type of connections to be used within the radio receiver set proper 33 is nonessential to my invention, exceptin so far as the detector tube leads P and F1, and those to antenna A and to ground Gd. are concerned, and as such l"? e er. EQE itQ iiP is en ra a s well known in the art, I have not considered it necessary to add an elaborate description thereof, but have felt that the showing made in Figure 2 would be sufficient, confining my further description to those points of contact with the leads F1, F2, and P1, emanating from my control-box H, shown at the right of the figure. 1

An enclosing metallic shield 80 preferably surrounds the entire amplifying equipment, however, and is directly connected both withthe metal sheath pf cable 30, and with the groundlead Gd. of radio receiver set 33, as indicated. The I.,R. F.-condensers willpreferably be ganged.

The arrow points on .ends of leads P1, F1, and F2, at detector tube, show the positions at which contacts are made by the adapter of Figure 3, the break 8| in filament line F, being produced by the adapter itself, as later described.

No further new elements appear in Figure 2, that have not been already described.

In Figure 3, a developed cross-section of my adapter plug, which is to be inserted into the detector socket of the radio set, is shown, and

which in turn is to then receive the detector tube 1 of the said set, the base and prongs of which tube are shown as inserted in the top of the adapter illustrated, with the filament, grid, and plate prongs identified by the customary initial lettering, F, F, G, and P, respectively, while the adapter prongs just therebelow enter the similarly marked terminals in a receptacle or socket, (not shown), but preferably of the flat top type, and the adapter leads P1, F1, and F2, are carried over to the control box through the metal covcred cable indicated in Figure 2. Note that Pi is in effect a tap from prong P, whereas F1 and F2 are across the break 8| between the tube prong F' and the adapter prong-81 just below it, F1 and F2 being separated by insulating parts in the adapter, although this is. difficult to bring out clearly in the Figure 3 shown. The screw to which line P1 is attached, however, simply connects directly with the spring 80, and the adapter prong 89, thereby forming a tap connection from the tube prong 9|, against which the sp ing 90 bears.

ferring further to Figure 3, the break between lines F1 and F: is indicated at 8|, these lines connecting to the terminal screws 82 and 83, respectively, threaded into electrically separated metal inserts imbedded in the base of adapter 84 of insulating material such as Bakelite, the upper of which inserts mounts the spring 85 of copper or phosphor-bronze, which bears against the filament prong F mounted in the radio-receiver detector-tube base 86, while the lower inseat carries a metallic extension integral therewith, and in which the adapted F-prong 81 is firmly mounted.

The end of lead P1 is clamped under the screw 88, also threaded in an insert bushing which has a metallic extension in which the adapter P- prong 89 is mounted, and which likewise carries the conducting spring 90, adapted to bear firmly upon the tube P-prong 9!, also mounted in base 86. The adapter G-prong mounted in a metalbush insert and carrying a similar spring to contact with the G-prong of tube, is indicated at 92, while 93 shows the similarly devised adapter-totube-base F-prong connection and spring. The G and F connections last mentioned have no screw and wire-lead connections attached thereto. A punched or drilled insulating plate for properly positioning the entrance of prongs on tube-base i8, is firmly pressed into adapter 84, as indicated at 94. l

The separate itemization of every minute detail-part in adapter has not been deemed necessary, so long as the exposition was clear, in view of space limitations.

It will be understood of course, that in the actual tube base and adapter used, the various prongs will be distributed in a pattern of usual type, and that for screen grid or alternating current heater tubes, still further prongs may be present, without affecting the items relevant to my invention, and the proper socket changes therefor will be self evident without further showing.

This completes the showing of parts of my invention, and of the apparatus to be used in more or less close association therewith. It will have been noted by anyone who has ever picked up broadcast programs by a radio receiver set, that where such programs are initiated say 3000 miles away and brought across country as audio frequency impulses by properly designed loaded telephone transmission lines, suitably transposed, and then broadcast through space at radio frequency by two stations, one of which is very close to the receiver, and the other ofi some very considerable distance, that in the presence of severe static conditions, the program emanating from the nearby local station will be substantially free from atmospheric static, whereas the same program coming in through space from the more distant station, may be almost ruined thereby. In other words, that the transmission at audio frequencies over the ultra long distance line has introduced very little, if any, static and other distortion effects, whereas even a very moderate distance through space may completely ruin an initially very fine program. This superiority of the long distance metallic lines is specially true for such distances as can be utilized in lead-covered cables, where the grounded sheath substantially wipes out from entrance thereinto, all exterior static elements.

I now propose to extend this sheathed protection right into the customers premises, and at the same time utilize such sheathing as a means for prevention of access of many of the manmade varieties of static, such as already enumerated, and likewise as a convenient means for elimination of unauthorized tampering with the wire plant supplied to each customer on his premises.

Since the continuous metallic enclosure of the lines prevents access thereto by other parties than those suitably supplied with the control equipment shown, it becomes possible to charge a modest sum per month for the program service rendered, so that direct revenue can be obtained therefrom without recourse to the nuisance of a pay-box or coin-operated device, and the highly objectionable sponsoring of programs eventually eliminated, with the normally attendant advertising excesses indulged in in the majority of such cases.

Thus not only static and similar intrusions, but the everlastingly obnoxious and pernicious advertising injections, may be in time wiped out, and a source of real revenue provided, to compensate for the supply of real music, in wide variety, and other worth-while forms of entertainment, over channels of assigned numbers, accessible to my selector-switch 59, on customers premises.

Since the incoming programs would come in over twisted pairs, and the customers telephone service ditto, within the same cable, clear up to the instruments, and not via long, non-twisted service lines through the open air, and often with considerable spacing between the respective leads, it is believed that a great percentage of the vacuum-cleaner, switching lamp, and telephone-dialing noises now picked up from nearby houses will be eliminated by the apparatus of my invention.

Since the programs would come in over twisted-pairs, the separate channels provided will be almost clear of cross-talk, or the spillingover of any one program into an adjacent channel, as now is so characteristic an element of socalled radio reception.

But since there may occasionally be excellent programs coming in as at present through space, and which any given customer may elect to hear in preference to those which I have provided complete metallic circuits for, I have added the change-over switch 35 to permit such customer to quickly go over to normal radio frequency reception through space, by way of the antenna 9, and associated switch connections 11, 18, and the lead to A on his radio receiver set.

This throw of the switch 35, by means of the handle 31, as shown in full lines in Figure 2, will short-circuit points 15 and 1%, thereby close' the break at 8|, in filament line to F side of detector tube, and thus light up this filament, provided main filament switch Sw. has been closed, and resistance R set properly.

It will be found that the plates of detector tube in the radio receiver set 33 and of the auxiliary amplifying tube 69, in control-box II, are left in parallel, but that the throwing 0! switch 35 from the dotted right to the solid-line left-hand position, by handle 31, will have opened up the detector filament circuit and closed the amplifier tube filament connection from negative side of A-battery, through resistance R, to negative lighting-bus and up to just below break 8|, out through line F; to point 14 on lower right side of the switch 35, out or point l3, through filament of tube 65 to point 1|, thence to 12 and ground, and back from ground to positive lighting-bus of the radio receiver set, which connects through the lighting-switch Sw. to positive side of A-battery.

Thus the throwing over of change-over switch 35 similarly throws over the filament lighting from tube 69, in box H, to the detector tube of radio receiver 33.

With one filament extinguished, the constant inter-connection of the plate elements of these two tubes will be of no material consequence, and is much simpler than trying to switch such plates back and forth also.

Throwing off either of the filaments will wipe out the transmission of any material signals through the respective tubes affected. Every listener to broadcast programs transmitted through space, to receivers non-equipped with automatic volume control devices, will have observed the periodic changes in strength of the incoming signals from distant stations, which is known as fading, and is especially noticeable near the sun-down and sun-up periods. During the minimum strength periods, the signals from certain broadcasting stations are also very seriously garb1ed" or altered by a so-called mushiness, until the distorted music or voice not eliminated by automatic volume control, but is entirely absent, along with all the "fading" just mentioned, from the programs received at audio-frequencies over the all-wire lines, suitably loaded and transposed, and which my invention utilizes.

It will be noted that I have provided means whereby my control-box and its associated wire lines may be readily attached electrically to a standard radio-receiver without material alteration of its parts, and that when so attached, such control-box and its associated connected elements will provide means for the monthly collection of revenue for the wire-delivered programs, which revenues can not be so successfully collected from customers enjoying any of the space-borne radio programs broadcast from present radio-frequency stations, and that I avoid use of all pay-box or coin-operated types of collecting means, which are such a great nuisance to the average customer.

In the use of the described apparatus of my invention, certain very definite advantages thus accrue from the elimination of much of the deleterious excess baggage now brought in along with the customary space-borne broadcasts, together with the decided clarification of the general signal train, and the wiping out of most of the obnoxious static influences.

Other important advantages accrue from the substantial elimination of fading, and its often attendant pronounced mushiness or garbling of signals as added to the'broadcast waves during their passage through space.

Equally important advantages accrue from the provision of means whereby the transmitted wire programs can be collected-for from the customer direct, eliminating the present necessity for sponsored programs and their many persistent advertising evils.

Added advantages accrue. from the substantial shielding-out of both atmospheric and manmade static influences, the roar of vacuumcleaner motors, the click-click of phone dialingsignals, the usual outbursts of lightning, and similar disadvantageous elements.

While I have shown and described a preferred form of my invention, many modifications may be made, both in its structure and in the mode of operation, without departing from either the spirit of said invention, or the scope of my broader claims.

What I claim is:

1. In a method of receiving and electively selecting between broadcast radio-frequency program-bearing waves, and wire-transmitted audio-frequency program-bearing impulses, the

steps comprising the thermionic amplification of said impulses, and the amplification and subsequent rectification thermionically of the said waves, the paralleling of the outputs of said rectification and said first mentioned amplification via a continuously maintained connection, the alternative energization of the electronemitter heaters for said rectification and said first mentioned amplification only, and the translation of the resultant output from said rectification and said first mentioned amplification in parallel, after further amplification of said resultant output by electro-thermionic means.

2. In a receiver of program bearing electric impulses, a radio-frequency receiving unit contain- 2,086,037 can not be recognized as such. This eflect is '5 ing a detector tube provided with a grid, a plate, and an electron-emitter, a socket for said tube, heating connections for said electron-emitter and connected with said socket, separate grid and plate connections for said tube also connected to said socket, an audio-frequency amplifier' having an output circuit and connected to receive signals from the said plate connection, and a sound translating means coupled to the output circuit of said amplifier, a separate audiofrequency amplifier device containing an electronic amplifier tube provided with a grid, a plate, and an electron-emitter, separate connections therefor, a signal transmitting means interconnecting the two said plate connections per manently, a source of supply of heating current, throw-over switching means arranged for connecting said source to the heating connections of the said electron-emitters of the detector tube and of the said electronic amplifier tube alternatively, means for supplying the two said grid connections with radio-frequency and with audio-frequency program bearing impulses respectively, and a switch mechanism provided with an enclosing housing and a lock and key therefor, and connected to control the supply of the said audio-frequency impulses.

3. In a receiver of impulses, as in claim 8 incoming cable with metal sheath, and containing program bearing lines, and separate telephone lines, tapped connections from said program bearing lines leading into a customer's premises, a metal shield over the said tapped connections and connected with the said sheath over said cable, a metallic housing having assembly means and mounted over the said separate amplifier device, and also over the said switch mechanism, and a clamp for the said metal shield, said clamp being mounted within said housing and arranged so as to be tightened only from the interior thereof, and by the aid of said key, said housing being built with all its said assembly means accessible from the 4. In a receiver of pr ra bearing electric impulses, as in claim an adapter having a plate connection, and electron-emitter heating connections, said adapter being mounted between the said detector tube and its said socket, and provided with a tap connection to the plate of the said detector tube whereby the said signal transmitting means connects the plate last mentioned to the plate of the said electronic amplifier tube of the separate audio-frequency amplifier device, said adapter also having a contact connecting with the electron-emitter heating connections of said detector tube, and a separate contact leading to the electron-emitter heating connections of said electronic amplifier tube of the separate amplifier device through the said switching means, whereby the latter can connect the said source of supply of heating current to the electron-emitter heating connections of said detector tube, and to those of said electronic amplifier tube of the said separate amplifier alternatively.

5. In an apparatus for receiving and electively choosing between space transmitted radio-frequency program bearing impulses, and wire transmitted audio-frequency impulses which are 70 also program bearing, a radio-frequency receiver containing an input circuit, a tuned radio-frequency amplifier stage connected thereto, a succeeding detector stage with a detector tube, and with plate, grid, and filament connections therefor, a subsequent audio-frequency amplifier stage having an output circuit, and a sound translating means connected to the said output circuit, a, separate audio-frequency amplifier stage having input leads and containing an amplifler tube, and having grid, plate, and filament connections therefor, an inter-connection between the plate of said detector tube and that of said amplifier tube last mentioned, throw-over switching means arranged to heat alternatively the filaments of the said tubes just mentioned, an antenna connected to the said input circuit of the receiver, and means for supplying the said input leads of the separate amplifier stage with program bearing audio-frequency electric impulses.

JAMES L. ADAMS, JR. 

